ACL MAIN RACE BEARINGS TIGHTER / LOOSER - HONDA K20 / K24 /B18C /B16A /B16BACL Race main bearing sets for your Honda K20A , K24A , K20Z B18C B16A B16B B20Z engines. When building your engine you might require tighter or looser main bearings to allow for crank wear after polishing or to have a clearance specific to your build. ACL offers a 0. 025mm tighter and looser main bearing. The unique combination of design, metallurgy and engineering come together to deliver what drivers expect from high performance Trimetal engine